Cooking apparatuses are home appliances used to heat and cook foods using electricity or gas. Electric hobs, which have been recently introduced in the market, include a heating source and a plate disposed above the heating source so as to heat a container placed on the plate using the heating source for cooking food contained in the container. A sheath heater, which includes a metal tube and a heating element sealed inside the metal tube, is usually used as the heating source of the electric hob.